1. Technical Field
The present invention relates to a flat panel display device and, more particularly, to an organic light emitting diode (OLED) having a unit for preventing formation of static electricity between a polarization plate and a substrate.
2. Related Art
In general, active-matrix organic light-emitting diodes (AMOLEDs) include a plurality of pixels arranged on a substrate. Each of the pixels includes at least one switching thin film transistor, one driving thin film transistor, a capacitor, and an organic electroluminescence (EL) element. An organic EL element is a self emission element which is driven by a thin film transistor. The organic EL element includes an anode electrode, an organic layer having a light emitting layer, and a cathode electrode, and it emits light from the light emitting layer of the organic layer according to voltages applied between the anode electrode and the cathode electrode.
Since the thin film transistor and the capacitor that form an OLED include an electrode made of a metallic material and an interconnection, external light is reflected by the metal electrode and interconnection so that the contrast of the OLED is greatly degraded.
The contrast of a flat panel display device, such as an OLED, is greatly reduced according to the intensity of external light. Thus, in the conventional OLED, a polarization plate is attached to a substrate so as to prevent reduction of contrast caused by external light.
An organic electroluminescence display device includes an organic electroluminescence (EL) display panel, a polarization plate, and a bracket for supporting the organic EL display panel. The organic EL display panel includes an upper substrate and a lower substrate. The organic EL display panel further includes an organic EL element formed between the upper substrate and the lower substrate.
In the organic electroluminescence display device having the above structure, static electricity induced between the polarization plate and the substrate causes malfunction of the organic EL element or affects the electrostatic capacity of a capacitor so that picture quality is lowered. In addition, due to the static electricity induced between the polarization plate and the substrate, an image display region is destroyed so that a desired image cannot be displayed.